Power trains are typically mechanical and electrical systems that generate and deliver power. An example of a power train is a turbine and generator coupled by a load coupling. The turbine applies torque to the load coupling which drives the generator that produces electrical power.
Vibrations in the power train are induced by cyclical variations in the torque or other forces applied to or by the power train. If the frequencies of these cyclical variations coincide with the natural frequencies of the power train, the cyclical variations may cause excessive torsional vibrations in the power train.
Power trains are often designed to operate away from their torsional natural frequencies. Despite well intentioned designs, power trains may experience cyclical variations in torque at frequencies at or near the natural frequencies. Under these cyclical variations, the power train may excessively vibrate and be damaged. There is a long felt need for devices and methods to adjust the inertia and natural torsional frequencies of a power train and other rotating bodies.
The turbine and generator in an industrial power train are typically large and heavy devices. A turbine may be an industrial gas turbine or steam turbine, which are large and heavy power generation units. Similarly, the generators may be large generators used by utilities to produce electrical power. Due to their large size and mass, it is difficult to modify the turbines and generators sufficiently to shift the natural frequencies at which they vibrate after they have been installed. There is a long felt need to adjust the inertia and natural torsional frequencies of industrial power trains that does not require substantial changes to the turbines or generators.
Currently known approaches to adjusting the inertial and natural torsional frequencies of such power trains involve the use of additional masses arranged about the load coupling. However, these currently known approaches may in some cases require deformation of the load coupling to retain these masses during operation.
Accordingly, methods and apparatus for adjusting torsional natural frequencies of power trains which do not require deformation of the load coupling are desired in the art. In particular, retention methods and apparatus for masses added to the load coupling that do not require deformation of the load coupling would be advantageous.